API 5CT

TUSPIPE-TUBING-CASING-OCTG-API-5CT-N80

API 5CT

OCTG is short for Oil Country Tubular Goods and refers to the pipes used in oil and gas extraction. The API 5CT standard covers the OCTG coupling, threading, and materials connections used in drilling operations. It includes instructions on dimensions, sizes, wall thicknesses, materials grades, tolerance limits, and performance requirements. The API 5CT is widely used in the oil and gas industry for both onshore and offshore drilling operations. OCTG manufacturers need to adhere to the standards set out in the API 5CT to ensure that their products are compatible with the oil and gas industry’s equipment and operations. By following the API 5CT, manufacturers can be confident that their OCTG products will be able to meet the demands of the oil and gas industry.

Why choose tuspipe for for Your Oil & Gas Needs?

pipe-icon

TUSPIPE stands tall as an indispensable ally for the oil and gas industry. Our pipes serve as the very lifelines that efficiently channel vital resources. Understanding the criticality of high-performing pipes in this sector, we engineer our products to withstand the rigorous demands and aggressive environments typical of oil and gas applications. Our pipes are compliant with the stringent API 5CT standards for casing and tubing, ensuring unmatched strength and durability. Additionally, catering to the diverse requirements of the oil and gas sector, TUSPIPE offers a variety of thread types including but not limited to BTC, LTC, STC, and premium threads, which ensure secure and reliable connections. Choose TUSPIPE for pipes that meet the industry’s highest standards, tailored to optimize your operations in the oil and gas sector.

Play Video about Tianjin United Steel Pipe Co., Ltd office building

Steel Grade of API 5CT Standard

  • Group 1: All casing and tubing in Grades with H, J, K, N and R
  • Group 2: All casing and tubing in Grades with C, L, M and T
  • Group 3: All casing and tubing in Grade P
  • Group 4: All casing in Grade Q

Dimensions and Sizes of API 5CT Casing and Tubing

- Specification & Size of API 5CT Tubing

DN O. D. Weight W. T. End Processing
Non-upset coupling-thread Upset coupling-thread Steel Grade
Inch mm lb./ft. lb./ft. Inch mm H40 J55 L80 N80 C90 T95 P110
2 3/8 2.375 60.32 4 0.167 4.24 PU PN PN PN PN PN
4.6 4.7 0.19 4.83 PNU PNU PNU PNU PNU PNU PNU
5.8 5.95 0.254 6.45 PNU PNU PNU PNU PNU
6.6 0.295 7.49 P P P
7.35 7.45 0.336 8.53 PU PU PU
2 7/8 2.875 73.02 6.4 6.5 0.217 5.51 PNU PNU
7.8 7.9 0.276 7.01
8.6 8.7 0.308 7.82 PLB PLB PLBE PLB
9.35 9.45 0.34 8.64 PLB PLB PLBE PLB
10.5 0.392 9.96 PLB PLB PLB PLB
11.5 0.44 11.18 PLB
3 1/2 3.5 88.9 7.7 0.216 5.49 PN PN PN PN PN PN
9.2 9.3 0.254 6.45 PNU PNU PNU PNU PNU PNU PNU
10.2 0.289 7.34 PN PN PN PN PN PN
12.7 12.95 0.375 9.52 PNU PNU PNU PNU PNU
14.3 0.43 10.92 P P P
15.5 0.476 12.09 P P P
17 0.53 13.46 P P P
4 4 101.6 9.5 0.226 5.74 PN PN PN PN PN PN
11 0.262 6.65 PU PU PU PU PU PU
13.2 0.33 8.38 P P P
16.1 0.415 10.54 P P P
18.9 0.5 12.7 P P P
22.2 0.61 15.49 P P P
4 1/2 4.5 114.3 12.6 12.75 0.271 6.88 PNU PNU PNU PNU PNU PNU
15.2 0.337 8.56 P P P
17 0.38 9.65 P P P
18.9 0.43 10.92 P P P PLB
21.5 0.5 12.7 P P P PLB
23.7 0.56 14.22 P P P PLB
26.1 0.63 16 P P P PLB
P——Plain;N—— Non-upset coupling-thread;U—— Upset coupling-thread; L——Integral

- Specification & Size of API 5CT Casing

DN O. D. Weight W. T. End Machining Form
Steel Grade
Inch mm lb/ft kg/m Inch mm H40 J55 L80 N80 C90 P110
K55 T95
4 1/2 4.5 114.3 9.5 14.14 0.205 5.21 PS PS
10.5 15.63 0.224 5.69 PSB
11.6 17.26 0.25 6.35 PSLB PLB PLB PLB PLB
13.5 20.09 0.29 7.37 PLB PLB PLB PLB
15.1 22.47 0.337 9.56 PLB
5 5 127 11.5 17.11 0.22 5.59 PS
13 19.35 0.253 6.43 PSLB
15 22.32 0.296 7.52 PSLB PLB PLB PLBE PLB
18 26.79 0.362 9.19 PLB PLB PLBE PLB
21.4 31.85 0.437 11.1 PLB PLB PLB PLB
23.2 34.53 0.478 12.14 PLB
24.1 35.86 0.5 12.7 PLB
5 1/2 5.5 139.7 14 20.83 0.244 6.2 PS PS
15.5 23.07 0.275 6.98 PSLB
17 25.3 0.304 7.72 PSLB PLB PLB PLBE PLB
20 29.76 0.361 9.17 PLB PLB PLBE PLB
23 34.23 0.415 10.54 PLB PLB PLBE PLB
26.8 39.88 0.5 12.7
29.7 44.2 0.562 14.27
32.6 48.51 0.625 15.88
35.3 52.53 0.687 17.45
38 56.55 0.75 19.05
40.5 60.27 0.812 20.62
43.1 64.14 0.875 22.22
6 5/8 6.625 168.28 20 29.76 0.288 7.32 PS PSLB
24 35.72 0.352 8.94 PSLB PLB PLB PLBE PLB
28 41.67 0.417 10.59 PLB PLB PLBE PLB
32 47.62 0.475 12.06 PLB PLB PLBE PLB
7 7 177.8 17 25.3 0.231 5.87 PS
20 29.76 0.272 6.91 PS PS
23 34.23 0.317 8.05 PSLB PLB PLB PLBE
26 38.69 0.362 9.19 PSLB PLB PLB PLBE PLB
29 43.16 0.408 10.36 PLB PLB PLBE PLB
32 47.62 0.453 11.51 PLB PLB PLBE PLB
35 52.09 0.498 12.65 PLB PLB PLBE PLB
38 56.55 0.54 13.72 PLB PLB PLBE PLB
42.7 63.54 0.625 15.88
46.4 69.05 0.687 17.45
50.1 74.56 0.75 19.05
53.6 79.77 0.812 20.62
57.1 84.97 0.875 22.22
7 5/8 7.625 193.68 24 35.72 0.3 7.62 PS
26.4 39.29 0.328 8.33 PSLB PLB PLB PLBE PLB
29.7 44.2 0.375 9.52 PLB PLB PLBE PLB
33.7 50.15 0.43 10.92 PLB PLB PLBE PLB
39 58.05 0.5 12.7 PLB PLB PLBE PLB
42.8 63.69 0.562 14.27 PLB PLB PLB PLB
45.3 67.41 0.595 15.11 PLB PLB PLB PLB
47.1 70.09 0.625 15.88 PLB PLB PLB PLB
51.2 76.19 0.687 17.45
55.3 80.3 0.75 19.05
8 5/8 8.625 219.08 24 35.72 0.264 6.71 PS
28 41.62 0.304 7.72 PS
32 47.62 0.352 8.94 PS PSLB
36 53.57 0.4 10.16 PSLB PLB PLB PLBE PLB
40 59.53 0.45 11.43 PLB PLB PLBE PLB
44 65.48 0.5 12.7 PLB PLB PLBE PLB
49 72.92 0.557 14.15 PLB PLB PLBE PLB
9 5/8 9.625 244.48 32.3 48.07 0.312 7.92 PS
36 53.57 0.352 8.94 PS PSLB
40 59.53 0.395 10.03 PSLB PLB PLB PLBE
43.5 64.73 0.435 11.05 PLB PLB PLBE PLB
47 69.94 0.472 11.99 PLB PLB PLBE PLB
53.5 79.62 0.545 13.84 PLB PLB PLBE PLB
58.4 86.91 0.595 15.11 PLB PLB PLB PLB
59.4 88.4 0.609 15.47
64.9 96.58 0.672 17.07
70.3 104.62 0.734 18.64
75.6 112.5 0.797 20.24
10 3/4 10.75 273.05 32.75 48.74 0.279 7.09 PS
40.5 60.27 0.35 8.89 PS PSB
15.5 67.71 0.4 10.16 PSB
51 75.9 0.45 11.43 PSB PSB PSB PSBE PSB
55.5 82.59 0.495 12.57 PSB PSB PSBE PSB
60.7 90.33 0.545 13.84 PSBE PSB
65.7 97.77 0.595 15.11 PSB PSB
73.2 108.93 0.672 17.07
79.2 117.86 0.734 18.64
85.3 126.94 0.797 20.24
11 3/4 11.75 42 62.5 0.333 8.46 PS
47 69.94 0.375 20.24
54 80.36 0.435 8.46
60 89.29 0.489 9.53
65 96.73 0.534 11.05
71 105.66 0.582 14.42
13 3/8 13.375 339.73 48 71.43 0.33 8.38 PS
54.5 81.1 0.38 9.65 PSB
61 90.78 0.43 10.92 PSB
68 101.19 0.48 12.19 PSB PSB PSB PSB PSB
72 107.15 0.514 13.06 PSB PSB PSB PSB
16 16 406.4 65 96.73 0.375 9.53 PS
75 111.61 0.438 11.13 PSB
84 125.01 0.495 12.57 PSB
109 162.21 0.656 16.66 P P P P
18 5/8 18.625 473.08 87.5 130.21 0.435 11.05 PS PSB
20 20 508 94 139.89 0.438 11.13 PSL PSLB
106.5 158.49 0.5 12.7 PSLB
133 197.93 0.635 16.13 PSLB
P——Plain;S——Short-thread;L——Long-thread;B——Buttress thread;E——Extreme thread

Chemical Composition (%) of API 5CT

Chemical Composition of API 5CT,Mass Fraction(%)
Group Grade Type C Mn Mo Cr Ni Cu P S Si
min. max. min. max. min. max. min. max. max. max. max. max. max.
1 H40 0.03 0.03
J55 0.03 0.03
K55 0.03 0.03
N80 1 0.03 0.03
N80 Q 0.03 0.03
R95 0.45 1.9 0.03 0.03 0.45
2 M65 0.03 0.03
L80 1 0.43 1.9 0.25 0.35 0.03 0.03 0.45
L80 9Cr 0.15 0.3 0.6 0.9 1.1 8 10 0.5 0.25 0.02 0.01 1
L81 13Cr 0.15 0.22 0.25 1 12 14 0.5 0.25 0.02 0.01 1
C90 1 0.35 1.2 0.25 0.85 1.5 0.99 0.02 0.01
T95 1 0.35 1.2 0.25 0.85 0.4 1.5 0.99 0.02 0.01
C110 0.35 1.2 0.25 1 0.4 1.5 0.99 0.02 0.005
3 P110 0.03 0.03
4 Q125 1 0.35 1.35 0.85 1.5 0.99 0.02 0.01
a. The carbon content for L80 may be increased up to 0, 50 % maximum if the product is oil-quenched.
b. The molybdenum content for Grade C90 Type 1 has no minimum tolerance if the WT is less than 17, 78 mm.
c. The carbon content for R95 may be increased up to 0, 55 % maximum if the product is oil-quenched.
d. The molybdenum content for T95 Type 1 may be decreased to 0, 15 % minimum if the WT is less than 17, 78 mm.
e. For EW Grade P110, the phosphorus content shall be 0,020 % maximum and the sulfur content 0,010 % maximum
NL = no limit. Elements shown shall be reported in product analysis.

Mechanical Properties of API 5CT

Mechanical Properties
Group Grade Type Total Yield Strength (Mpa) Tensile Hardness max
% min. max. MPa HRC HBW
1 H40 0.5 276 552 414
J55 0.5 379 552 517
K55 0.5 379 552 655
N80 1 0.5 552 758 689
N80 Q 0.5 552 758 689
R95 0.5 655 758 724
2 M65 0.5 445 586 586 22 235
L80 1 0.5 552 655 655 23 241
L80 9Cr 0.5 552 655 655 23 241
L81 13Cr 0.5 552 655 655 23 241
C90 1 0.5 621 724 689 25.4 255
T95 1 0.5 655 758 724 25.4 255
C110 0.7 758 828 793 30 286
3 P110 0.6 758 965 862
4 Q125 1 0.65 862 1034 931
a. In case of dispute, laboratory Rockwell C hardness testing shall be used as the referee method.
b. No hardness limits, but the maximum variation is controlled by manufacturer acc API 5CT.

API 5CT Dimensional Deviation

Items Allowable Deviation
Out Diameter D ≤ 101.60mm ± 0.79mm
D ≥ 114.30mm + 1.0%, -0.5%
Wall Thickness -12.50%
Mass (Single Lengths) +6.5%, -3.5%

Length Range of API 5CT

Length
Item Scope 1 Scope 2 Scope 3
Tubing 6.10-7.32m 8.53-9.75m
Casing 4.88-7.62m 7.62-10.36m 10.36-14.63m

Test and inspection of API 5CT Tubing and Casing

- Hydrostatic Test

Hydrostatic testing is a critical quality control measure during the production of steel pipe. The purpose of the hydrostatic test is to verify that the seam welds and pipe body can withstand the required internal water pressure without leaking. To conduct the test, water is pressurized and injected into the pipe. Once the water pressure reaches the specified level, the pipe is subjected to a thorough examination for leaks. Any leaks that are found are repaired and the hydrostatic test is repeated until the pipe passes inspection. This process ensures that the finished product can safely transport water or other fluids under high pressure without leaking.

- Bend Test

During the production of an API 5CT tubing and casing pipe, a bending test is conducted to ensure the quality of the weld. This test involves taking a sample of the steel pipe and subjecting it to a bending force. The results of the test are then evaluated to determine if there are any cracks in the weld. If no cracks are found, the pipe is deemed to be of acceptable quality. However, if cracks are found, the pipe is rejected and must be repaired or replaced. The bending test is an important part of the production process, as it helps to ensure that the final product is of high quality and will perform as intended.

- Flattening Test

Flattening tests are typically performed during the quality control testing of steel pipes, such as those produced according to the API 5CT specification. The flattening test is used to assess a sample pipe’s resistance to longitudinal deformation (i.e. crack growth) and its ability to maintain its shape under stress. The test is conducted by first welded a ring onto one end of the pipe sample. The other end of the sample is then placed in a jig, which compresses the entire length of the pipe along its longitudinal axis. Once the desired compression is achieved, the jig is released and the sample is removed for inspection. Any cracks or deformations that have occurred during the test are then documented and analyzed. The results of the flattening test can be used to assess the quality of the pipe and its suitability for use in various applications.

- CVN Impact Test

When it comes to tubing and casing pipe production, the impact test is an important quality control measure. Also known as the Charpy test, this test is used to assess a material’s ability to withstand impact. The test involves striking a specimen with a hammer and then measuring the amount of energy that is absorbed. The results are then compared to a standard to determine whether the material meets the required specification. There are three main areas that are tested during impact testing: the pipe body, the weld sea, and the heat-affected zone. By understanding the importance of this test, manufacturers can ensure that their steel pipes meet the required standards for strength and durability.

API 5CT Pipe Ending Processing

- Flat End / Plain End

A plain end, also known as a flat end or square cut, is a type of steel pipe that has a flat end rather than a beveled or threaded end. Plain end pipes are more common in larger diameter pipes and are typically used for carrying fluids under high pressure. One advantage of plain end pipe is that it is easier to weld or connect to other types of pipe. However, plain end pipe is less able to withstand external forces, such as those from wind or waves, and is more susceptible to damage from impacts. As a result, plain end pipe is often used in applications where it will be buried or otherwise protected from the elements.

- Threaded End

Casing is a steel pipe that is used to line the borehole of a drilling well. It is important to use casing in order to prevent collapse of the borehole and to protect the equipment that is being used. Casing is also used to keep out water, gas, and oil from entering the well. The threaded end on a casing pipe is used for making a connection with a screw. This type of connection is known as a threaded joint. In order to make this connection, a casing coupler is used. The coupler is screwed onto the end of the pipe and then the two pipes are connected together with a screw.

- Rounded Nose

A rounded nose on a casing pipe is simply a threaded connection that has been machined to have a rounded, rather than flat, end. This type of connection is often used when space is limited, such as in tight corners or other difficult-to-reach areas. In addition, rounded noses are less likely to snag on surrounding objects, making them ideal for use in high-traffic areas. Although they are more expensive than traditional threaded connections, the increased safety and durability of rounded noses make them well worth the investment.

What is API 5CT OCTG?

Oil country tubular goods (OCTG) is a family of steel pipe products used in the drilling, completion, and production of oil and gas wells. And, API 5CT is the standard for the group of products. OCTG casing and tubing are essential elements in the well construction process, as they provide support and protection for the well bore. Casing is installed first, followed by tubing. The casing is typically made of steel or other strong materials that can withstand the high pressure and temperature of the reservoir. Tubing is also made of steel, but it is thinner walled and carried inside the casing. OCTG products are manufactured to meet specific specifications that are based on the type of well being drilled. For example, sour service casing must be able to resist corrosion from hydrogen sulfide gas. Deepwater casing must be able to withstand the high pressures found at great depths. Ultimately, OCTG products play a vital role in ensuring the safety and efficiency of oil and gas drilling operations.

What is the Difference between API 5CT Casing and Tubing?

API 5CT casing is a tube that is placed in a wellbore in order to protect the wellbore from contamination. Casing is also used to stabilize the wellbore and keep it secure. Drilling and casing operations occur alternately, with the drill string being removed at predetermined intervals. API 5CT tubing is used to carry petroleum from the depths of the well to the surface. Oil and gas may sometimes self-elevate to the surface; however, pumps are typically required in order to bring these fluids to the surface. Tubing typically has a smaller diameter than casing. The main purpose of tubing is to transport petroleum from the well to an external location.

Line-Pipe
Line Pipe
Slotted-Liner
Slotted Liner
Pipe-Fabrication-Spooling
Steel Fabrication
pipe-fittings
Pipe Fittings
Scroll to Top

Get A Quote Now

Fill in the form below and our team will be happy to assist you